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ENVIRONMENTAL CONTROL REQUIREMENTS :
POOL WATER TEMPERATURE :
The pool water requires to be heated to an acceptable temperature. Within a typical indoor pool, the pool water
is normally heated to a temperature between 26°C and 31°C. The vast majority of the heat loss from the pool
water is through evaporation from the pool surface into the pool hall air.
POOL HALL AIR TEMPERATURE :
The pool hall air requires to be heated to an acceptable temperature.
Ideally, in order to limit heat loss and evaporation from the pool water surface, the pool hall air temperature
should be maintained slightly higher than that of the pool water. For example, if the pool water temperature is
28°C, the pool hall air temperature should be maintained at 30°C.
It should be noted that, although such high air temperatures provide a pleasant environment for suitably attired
bathers, for whom wetted skin enhances the chilling effect on the body, such conditions may prove
uncomfortably warm for other activities and for fully clothed spectators.
POOL HALL HUMIDITY :
The water evaporated from the pool surface is present in the pool hall air in the form of humidity.
This moisture laden humid air also contains the majority of the heat lost from the pool water and therefore is rich
in energy. This energy is referred to as latent heat.
The amount of humidity is expressed as % Relative Humidity (% R.H.). The amount of moisture which the air
can hold before condensation starts to occur is 'relative' to the temperature of the air.
Therefore, it is possible to increase the ‘relative humidity’simply by reducing the air temperature, although the
actual quantity of moisture in the air would remain unaltered. Likewise, a decrease in ‘relative humidity’can be
achieved simply by increasing the air temperature.
The cooler the air, the higher the ‘relative humidity’reading and the easier condensation will occur.
WHAT IS THE IDEAL HUMIDITY LEVEL?
Within a typical indoor pool, the humidity would be controlled at around 60-65% R.H., which would provide
pleasant conditions for bathers and minimal condensation on the pool hall structure. If the relative humidity is
reduced further, then the rate of evaporation, and therefore the heat loss, from the pool water is unnecessarily
increased together with the requirement for dehumidification.
HOW IS THE HUMIDITY LEVEL CONTROLLED?
If the pool hall humidity level is not limited, then heavy condensation will occur on the pool hall building structure,
leading to rapid deterioration of the decor and possible eventual structural failure.
To prevent this, a method of 'dehumidification' must be employed.
In the past fuel costs were comparatively cheap and, therefore, it was possible to simply extract the humid
energy laden pool air to out side without any attempt to recover the heat, whilst replacing it with cooler fresh air
which required rapid heating to an acceptable temperature.
Given present day fuel costs, such a wasteful approach would, understandably, prove prohibitively expensive to
operate. Modern systems therefore utilise methods of energy recovery, often using refrigeration technology or
air-to-air heat exchangers.
